Denial of rehearing was anticipated – of the estimated 1,500 requests for rehearing each year, the Ninth Circuit grants rehearing in only 15-25 cases a year. It is more noteworthy that the court used the Petition for Rehearing process to amend its February 1 decision to attempt to bolster its legal analysis and conclusions. In that decision, the Ninth Circuit held that Maui violated Clean Water Act (CWA) Section 301 by discharging pollutants from a point source that eventually reach a CWA jurisdictional water via groundwater, without a CWA Section 402 National Pollutant Discharge Elimination System (NPDES) permit.

The court added language to two footnotes:

We are not suggesting that the [Clean Water Act] CWA regulates all groundwater. Rather, in fidelity to the statute, we are reinforcing that the Act regulates point source discharges to a navigable water, and that liability may attach when a point source discharge is conveyed to a navigable water through groundwater.

Our approach is firmly grounded in our case law, which distinguishes between point source and nonpoint source pollution based on whether pollutants can be “traced” or are “traceable” back to a point source.

These additions are intended to support the Ninth Circuit’s adoption of a new indirect discharge theory to hold Maui County liable under the CWA because (1) the County discharged pollutants from a point source (i.e., the wells); (2) the pollutants are fairly traceable from the point source to a navigable water, such that the discharge is the functional equivalent of a discharge into the navigable water; and (3) the pollutant levels reaching navigable water are more than de minimis.

The timing of the Court’s amendments is interesting given the February 20 Federal Register notice published by the EPA requesting comments on the Agency's previous statements regarding whether point source discharges through groundwater that has a direct hydrologic connection to jurisdictional surface water may be subject to regulation under the CWA.

The Ninth Circuit’s ruling may have far-reaching implications including an expansion of the universe of sources subject to NPDES permit requirements, and increased exposure to citizen suit enforcement. NACWA is currently participating in two other groundwater liability cases pending in the Second and Fourth Circuits.

The County of Maui has 90 days from March 30 to file a petition for review with the US Supreme Court.